Epidemiology is currently the science of public health mad file major intellectual system, along with economics, for studying, justifying and developing public health policy. Despite its deep influence on medicine, science, health policy and American culture over the past 40 years, there is presently no systematic history of epidemiology in the United States, particularly for the second half of the 20th century. The objective of this proposal is to write a social and intellectual history of the origins, development, and impact of one of the most important areas of epidemiology during the last century, that of coronary heart disease (CHD). The work will begin early in the 20th century, just before the "epidemiological transition," when mortality from heart disease and cancer surpassed deaths from communicable disorders. With this introductory period (1900-1945) as prologue, the book will then focus on the emergence, after World War II, of an epidemiology capable of defining, modeling, and quantifying chronic (heart) disease and of proposing clinical interventions. That history will continue into the 1960s, when epidemiology began to emerge from relative obscurity to become a recognized science and a party to health policy decision-making; then to the 1970s when epidemiology, with a body of knowledge, training programs, textbooks and journals, became a fully formed discipline at the heart of public health. It will end in the 1990s, when the successful paradigm developed in the decades after World War II--the multiple risk factor, individual-level analysis closely associated with coronary heart disease epidemiology--was severely questioned by experts both within and outside the field. Data for this project will come from archival sources, the medical and epidemiological literature, taped interviews, and publications in the history of medicine, public health, statistics, insurance and risk.